1. Field of the Invention
The present invention relates to an optical transmission system for transmitting signal light through an optical fiber transmission line, and to an optical fiber and others for compensating for chromatic dispersion of the entire optical fiber transmission line.
2. Related Background Art
An optical transmission system uses a Single Mode Fiber (SMF) in conformity with ITU-T G652.C, comprised primarily of silica glass, as an optical fiber transmission line for transmitting signal light. The C-band (1530 nm-1565 nm) is used as a wavelength band of signal light and the L-band (1565 nm-1625 nm) is also used. The SMF has the chromatic dispersion of 12 ps/nm/km or more but 21 ps/nm/km or less and the dispersion slope of 0.04 ps/nm2/km or more but 0.10 ps/nm2/km or less at the wavelength of 1550 nm.
When signal light is transmitted through the optical fiber transmission line consisting of such SMF, the waveform of signal light is deteriorated by chromatic dispersion in the SMF and it makes high-speed transmission difficult. Therefore, a dispersion compensator to compensate the chromatic dispersion of the optical fiber transmission line consisting of the SMF is inserted into the signal light transmission line. Examples of the dispersion compensator used commonly include a dispersion compensating fiber with chromatic dispersion negative in the C-band, and a dispersion compensating fiber with negative dispersion slope to compensate for wavelength dependence of chromatic dispersion as well (e.g., cf. Patent Documents 1-4).
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-169049
[Patent Document 2] Japanese Patent Application Laid-Open No. 2003-84162
[Patent Document 3] Japanese Patent No. 3602152
[Patent Document 4] Japanese Patent No. 3247221
[Non-patent Document 1] ECOC-IOOC Proceedings Vol. 3, Paper We4. P. 14-15, 2003